Key points

Temporary asylum in Russia can be granted for a year, and can be extended.

Snowden has been holed up in Sheremetyevo airport for three weeks.

Russia does not want Snowden's presence to damage ties with US.

"For now he is not going to go anywhere. For now he plans to stay in Russia."

Mr Kucherena added that if Snowden were granted temporary asylum, he should have the same rights as other citizens and be free to work and travel in Russia.

The head of Russia's Federal Migration Service confirmed the agency had received Snowden's application.

WikiLeaks, which has been helping Snowden, said on Twitter he had applied for "a temporary protection visa".

Temporary asylum can be granted for up to a year, with the possibility of extension.

Mr Kucherena said he expected a decision on Snowden's asylum request "soon", though the Federal Migration Service has up to three months to decide on the application.

Snowden told human rights campaigners on Friday at a meeting in Sheremetyevo's transit area that he was seeking temporary asylum in Russia until he can travel safely to Latin America, where three countries have said they might take him in.

He has been unable to reach any of those countries - Nicaragua, Venezuela or Bolivia - because there are no direct flights from Moscow and he would risk having his passage barred by the US and its allies.

Case threatens ties between Russia, US

The case is an increasingly awkward problem for Russian president Vladimir Putin as Moscow and Washington try to improve relations, and he prepares for a summit with US president Barack Obama in Moscow in early September, just before a summit of G20 leaders in Russia.

"We have certain relations with the United States and we don't want you to damage our ties with your activity," Mr Putin said, referring to Snowden.

Asked to comment on what comes next for Snowden, the Russian president said: "How do I know? It's his life, his fate."

Mr Obama's administration repeated its call for Russia to send Snowden back to the United States.

"He is not a human rights activist, he is not a dissident. He is accused of leaking classified information," White House spokesman Jay Carney said.

"He is a United States citizen who has been charged with crimes, and ... he should be afforded every bit of due process here in the United States. And he should return here to face trial."